1. Technical Field
The present invention relates to an image forming apparatus and an image forming method.
2. Related Art
Up to now, in a recording apparatus for obtaining a color image by means of an electrophotography method, fundamental three primary colors are developed corresponding to respective image information and toner images thereof are sequentially superposed to obtain a color image. Specific known apparatus configurations are: a so-called four-cycle unit in which for each color a single photoreceptor drum has a latent image formed thereon, according to an image forming method, developed and then transferred onto a transfer member, this cycle being repeated for each color to obtain a color image; and a tandem unit in which for each color image forming unit a photoreceptor drum and a developing apparatus are provided and a transfer member moves to sequentially and continuously transfer a toner image to obtain a color image is known.
These are common in at least the point that a plurality of developing apparatuses for the respective colors is provided. Accordingly, in ordinary color image formation, four developing apparatuses for use with the three primary colors and black are necessary. Furthermore, in the tandem unit, corresponding to the respective four developing apparatuses, four photoreceptor drums are necessary and means for synchronizing the four image forming units is necessary. Accordingly, it cannot be avoided that an apparatus becomes large in size and the cost increases.